In the field of computer systems including a plurality of computers, techniques have been suggested from various viewpoints in regard to measures against failures.
For example, the computer system disclosed in Patent Literature 1 includes failure prediction means for predicting a failure in the computer, and the failure prediction means normally stops all services operating on the computer that is predicted to generate the failure as well as re-executes those services on another computer. Then, after all the services are re-executed on another computer, the failure prediction means stops the computer predicted to generate the failure.
This computer system is explained to transfer the services operating on the computer that is predicted to generate the failure before the failure occurs on the computer and normally stop the computer predicted to generate the failure without intervention of a system administrator.
Further, in a computer backup system disclosed in Patent Literature 2, a business computer (active system computer) includes an abnormality detecting sensor for detecting a breakdown sign in the computer and transmits electronic information that should be backed up to a backup computer via a network upon detection of the sign. When the backup computer receives the electronic information from the business computer, the backup computer saves the electronic information to a storage medium included therein.
This backup computer is explained to save the electronic information created on the business computer immediately before a disaster strikes.
Moreover, in a database system disclosed in Patent Literature 3, an active system device includes an active system TM (Transaction Manager) for processing transactions and an active system DBMS (Data Base Management System) for reflecting update data generated by the transaction. The standby system device includes a standby system TM that is notified of the update data from the active system TM and a standby system DBMS that synchronizes data content stored to the active system DBMS. The active system TM notifies the active system DBMS of the update data generated by executing the transactions as well as notifies the standby system TM by synchronous communication. The active system DBMS reflects the update data notified from the active system TM in a database managed by itself as well as notifies the standby system DBMS of the update data by asynchronous communication. The standby system TM stores the notified update data to a difference file, reads the update data from the difference file at a predetermined trigger, and notifies the standby system DBMS. The standby system DBMS reflects the update data obtained from the active system DBMS or the standby system TM in the database managed by itself.
According to this database system, when a synchronization technique of the database is used in which one computer organizes and transmits the update data together with control information of the update data while another computer assembles the update data based on the control information, and the update data is returned to the unit of transaction and reflected in another database, in the case of the failure during the process to organize the update data by one computer, it has been explained that the problem can be solved in which the database on one computer and the database on another computer cannot be synchronized, and thereby improving the reliability of database synchronization.
Note that although in the systems disclosed in Patent Literature 1 and 2, failure occurrence in the active system computer is learned by the abnormality detecting sensor or the failure prediction means included in the systems, for example as disclosed in Patent Literature 4, the technique is known for learning the failure occurrence by receiving disaster notification information that notifies predicted occurrence of disaster.